Short-distance communication using ultrasonic proximity sensor

Abstract

To provide a vehicle, a system, and a method that adapt ultrasonic sensing arrays for short-range communication with smart devices, parking infrastructure, and other vehicles.SOLUTION: An exemplary vehicle includes one or more ultrasonic sensors configured for proximity sensing and a controller configured to use the one or more ultrasonic sensors to receive an acoustic signal from a smart device. As another example, the exemplary vehicle includes one or more microphones configured for at least one of noise reduction, voice control, emergency vehicle detection, and proximity sensing, and a controller configured to use the one or more microphones to receive an acoustic signal from the smart device. The acoustic signal is in the frequency range of 18 kHz to 25 kHz (inclusive).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to ultrasonic proximity sensing systems for vehicles, and more particularly to the use of such systems to communicate with smartphones, other vehicles, occupancy sensors, or other devices. [Background technology]

[0002] Modern automobiles are equipped with an astounding number and variety of sensors. For example, cars are now routinely equipped with arrays of ultrasonic sensors to monitor the distance between the car and any nearby people, pets, vehicles, or obstacles. Manufacturers continue to create and develop new sales features for their vehicles, often necessitating the addition of new sensor types and configurations to support these new features. The commercial feasibility of these new sales features may depend on the cost and feasibility of integrating new sensor systems with the vehicle's existing infrastructure. New sales features may be more desirable if they can leverage the existing infrastructure for additional uses. Summary of the Invention

[0003] Accordingly, disclosed herein are exemplary vehicles, systems, and methods that adapt ultrasonic sensing arrays for near-field communication with, for example, smart devices, parking infrastructure, and other vehicles. As an example, an exemplary vehicle includes one or more ultrasonic sensors configured for proximity sensing and a controller configured to use the one or more ultrasonic sensors to receive acoustic signals from smart devices.

[0004] As another example, an exemplary vehicle includes one or more microphones configured for at least one of noise cancellation, voice control, emergency vehicle detection, and proximity sensing, and a controller configured to use the one or more microphones to receive acoustic signals from a smart device, the acoustic signals being in a frequency range of 18 kHz to 25 kHz (inclusive).

[0005] As yet another example, an exemplary method of operating an advanced driver-assistance system (ADAS) includes performing an ultrasonic proximity measurement via an ultrasonic proximity sensor of the ADAS using a first frequency range and communicating with a smart device via the ultrasonic proximity sensor using a second frequency range lower than the first frequency range.

[0006] As yet another example, an example vehicle includes one or more ultrasonic sensors configured for proximity sensing and a controller configured to use the one or more ultrasonic sensors to transmit data to a second vehicle or an ultrasonic occupancy sensor.

[0007] Each of the foregoing embodiments may be employed individually or together and may include one or more of the following features in any suitable combination: 1. The acoustic signal includes at least one of a lock command, an unlock command, and an alarm command. 2. The acoustic signal is in a frequency range of 18 kHz to 25 kHz, inclusive. 3. The acoustic signal is in a frequency range of 20 kHz to 23 kHz, inclusive. 4. Each of the one or more ultrasonic sensors includes a MEMS (micro-electromechanical system) microphone. 5. The smart device is a smartphone. 6. The controller is further configured to use the one or more ultrasonic sensors to transmit a second acoustic signal to the smart device, the acoustic signal and the second acoustic signal providing a two-way communication channel between the vehicle and the smart device. 7. The controller is further configured to use a plurality of ultrasonic sensors of the one or more ultrasonic sensors to steer the transmitted acoustic signal to the smart device. 8. The one or more ultrasonic transducers transmit a second acoustic signal to the smart device, the acoustic signal and the second acoustic signal providing a two-way communication channel between the vehicle and the smart device. 9. The second frequency range is in the band of 20 kHz to 23 kHz, inclusive. 10. The controller is further configured to use one or more ultrasonic sensors to receive data from a second vehicle or ultrasonic occupancy sensor. 11. The controller is further configured to use multiple ultrasonic sensors of the one or more ultrasonic sensors to steer a signal that conveys the transmitted data to the second vehicle or ultrasonic occupancy sensor. 12. The transmitted data includes vehicle registration information. 13. The transmitted data includes an identification of an owner or driver of the vehicle. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram of a user approaching an exemplary vehicle. [Diagram 2] FIG. 1 is a block diagram of an exemplary driving / parking assistance system. [Diagram 3] FIG. 1 is a circuit diagram of an example ultrasonic proximity sensor. [Figure 4]FIG. 2 is a block diagram of an exemplary bidirectional communication channel. [Diagram 5] FIG. 1 is a flow diagram of an example near-field communication method that may be implemented by a smart device. [Figure 6] FIG. 1 is a flow diagram of an exemplary short-range communication method that may be implemented by a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The drawings and the following description are not intended to limit the disclosure, but rather to provide a basis for those skilled in the art to appreciate all modifications, equivalents, and alternatives falling within the language of the claims. Although communication between a vehicle and a smart device is used to provide an illustrative context, the principles can be applied to vehicle communication with infrastructure and other vehicles.

[0010] As an example usage context, FIG. 1 shows a user 102 approaching a vehicle 104. The user 102 is holding a smart device 106 as the user 102 moves within close range, e.g., within a few meters. The smart device 106 may be a smartphone, a smart watch, a smart speaker, a smart pendant, or any portable or wearable electronic device with a speaker and programmable functionality, such as may be provided in the form of a downloadable software application. It is envisioned that the smart device has wireless connectivity, e.g., via Wi-Fi, a cell service network, or satellite, to facilitate software downloads and / or remote wireless communication to connect with one or more suitable Internet-accessible servers, although wireless connectivity is not a requirement.

[0011] The smart device 106 is preferably a personal item already owned by the user 102 and habitually worn on or in close proximity to the user. Many suitable commercially available and widely used smart devices (e.g., smartphones) generate sound or music from digital data streams having sampling rates of 44.1 kHz or 48 kHz. These sampling rates are the most common and will be adopted in the following description, although other sampling rates may be used and adopted.

[0012] The range of audible sound frequencies is generally considered to be 20 Hz to 20 kHz, although the hearing range of the average human decreases over time. Sensitivity decreases at the ends of this range to the point where near-ultrasonic frequencies (e.g., 18 kHz to 20 kHz) are detectable but not disturbing to most people. A device employing a sampling rate of 44.1 kHz can generate ultrasonic frequencies up to 22.05 kHz, and a device employing a sampling range of 48 kHz can generate ultrasonic frequencies up to 24 kHz. The present disclosure contemplates using smart devices to generate acoustic signals in the range of 18 kHz to 25 kHz, or more preferably in the range of 20 kHz to 23 kHz, or even more preferably in the range of 21 kHz to 22 kHz.

[0013] Using an appropriate software application, the smart device 106 can be configured to generate ultrasonic or near-ultrasonic signals to communicate with the vehicle 104. The generated acoustic signal can modulate a carrier frequency using amplitude modulation, phase modulation, frequency modulation, or a combination thereof (e.g., quadrature amplitude modulation, frequency hopping, multi-carrier modulation). The generated acoustic signal may additionally or alternatively employ up-chirps and down-chirps to represent channel symbols. The generated acoustic signal may employ a message frame syntax that begins each frame with a preamble to enable timing synchronization and channel training at the receiver. The frame may include a predefined header, a message payload, and a checksum. Error correction coding can be used to introduce controlled redundancy in the frame contents. Scrambling masks can be applied to the message header and payload for encryption and "whitening" of the channel spectrum.

[0014] In either case, the generated acoustic signal may include, for example, a selectable one of a lock command, an unlock command, and a sound alarm command, allowing the smart device 106 to function as a replacement for a traditional car key fob. This configuration offers a variety of potential advantages, as described further below.

[0015] As has become routine for modern vehicles, the exemplary vehicle 104 is equipped with an array of ultrasonic proximity sensors 108. Such sensors typically employ pulse-echo techniques to measure distances to nearby obstacles around the vehicle. The sensors 108 may include piezoelectric transducers for periodically generating ultrasonic bursts. These piezoelectric transducers may also detect reflections of acoustic bursts from nearby obstacles, although more recent sensor designs employ one or more MEMS (microelectromechanical systems) microphones to detect the reflections. The ultrasonic proximity sensors 108 may be expected to operate in the 40 kHz to 60 kHz frequency range, although it is noted herein that MEMS microphones may be expected to operate well into the audible range (and down to 10 kHz or less) and may even exhibit peak sensitivity in the 22 kHz to 34 kHz range. Thus, no hardware modifications are required to make the exemplary vehicle 104 sensitive to acoustic signals in the 18 kHz to 25 kHz range. The vehicle may be configured for near-field ultrasonic communication with firmware modifications to the sensor 108 and / or the vehicle's electronic control unit (ECU).

[0016] The communication may be, but need not be, unidirectional. The piezoelectric transducer is tuned to operate in the 40kHz to 60kHz range, and although performance is expected to degrade outside this range, it can be used to generate near-field acoustic signals in the 18kHz to 25kHz range without significant hardware modification. In some contemplated implementations, the vehicle 104 can employ an array of ultrasonic proximity sensors 108 to triangulate the location of the user 102, and then drive multiple transducers in stages to provide directional gain of the acoustic signal to the smart device 106, i.e., "steer" the acoustic signal. Many suitable smart devices 106 include microphones with sampling rates of 44.1kHz or 48kHz, which enable the smart device to receive ultrasonic or near-ultrasonic signals from the vehicle 104. Preliminary testing with a separation of about 2 meters between the device 106 and the sensor 108 indicates that baud rates of 500 symbols per second to about 600 symbols per second are readily achievable in each direction.

[0017] 2 illustrates a set of interconnected ECUs (electronic control units) 201-203 organized into a hierarchical bus topology. Of course, other topologies, including serial, parallel, star, and ring topologies, are also suitable and contemplated for use in accordance with the principles disclosed herein. Although multiple ECUs are shown and described herein, in some cases it may be preferable to have a single ECU perform various functions.

[0018] The first ECU 201 is coupled to an array of ultrasonic proximity sensors 108, each of which may include a ULS transducer and a MEMS microphone. The first ECU 201 may further be coupled to additional ultrasonic transducers 208 for additional zone coverage and / or acoustic signal gain, additional microphones 206, e.g., for noise cancellation, siren detection, voice control, and a radio frequency interface 204, e.g., for cellular network connectivity, satellite navigation, wireless services.

[0019] To provide automatic parking or other advanced features, the second ECU 202 may be connected to a set of actuators, such as a door lock actuator 210, a throttle actuator 212, a brake actuator 214, a steering actuator 216, and a turn signal actuator 218. The third ECU 403 may couple to a user interactive interface 220 to accept user input and provide displays of various measurements and system status. Using the interfaces, sensors, and actuators, the ECUs 201-203 may provide automatic parking, assisted parking, lane change assistance, obstacle and blind spot detection, and other desirable features.

[0020] 2 further illustrates a smart device 106 in communication with an ultrasonic proximity sensor 108, transmitting and / or receiving ultrasonic or near-ultrasonic acoustic signals. The sensor 108, operating alone or in combination with the ECU 201, can analyze messages received from the smart device and initiate actions such as locking or unlocking the doors.

[0021] 3 illustrates a block diagram of an example controller 302 of the sensor 108. The controller 302 employs input and output (IO) pins that are multiplexed to a selected one of a variety of IO protocol modules. 2Modules for the C (Inter Integrated Circuit) communication bus protocol, the SPI (Serial Peripheral Interface) communication bus protocol, and the DSI3 (Distributed System Interface 3rd Generation) communication bus protocol are shown as non-limiting examples only. Other contemplated protocols include those described in the LIN, CAN, and SENT standards. The IO bus 310 couples the various IO protocol modules to an embedded microprocessor (μP). For example, an AMBA (Advanced Microcontroller Bus Architecture) bus, such as AHB-Lite (Simplified Advanced High Performance Bus), can be used to couple the embedded microprocessor to various other functional blocks of the sensor controller 302. Such blocks include, for example, a non-volatile firmware (FW) memory, a volatile working memory (MEM), a digital signal processor (DSP), a power-on reset (POR) module, a microphone signal receiver (RX M ) for ADC (Analog-to-Digital Converter), Transducer Signal Receiver (RX T ) for the second ADC, driving current for the transmitter (TX I ), and the driving voltage transmitter (TX V ) may be included. (The transmitters generate the drive signal for the ultrasonic transducer as a controlled current or voltage, respectively.) A multiplexer may couple a selected one of the transmitters to an output pin to drive the piezoelectric transducer 304. FIG. 3 further shows an embedded oscillator (OSC) that generates one or more clock signals for various other blocks, optionally including a carrier frequency for the transmitter and receiver. The POR module may control distribution of the clock signals to enable sleep modes for unnecessary components and other power saving features.

[0022] The IO pins couple the sensor controllers 302 directly or indirectly (e.g., via a DSI3 bus master) to an ECU (electronic control unit). The ECU may communicate commands to each of the sensor controllers to, for example, set values ​​for various configuration parameters of the sensors, initiate transmission of acoustic bursts, and collect signal data or other measurements. A microprocessor within each sensor controller 302 operates according to firmware and stored configuration parameters to parse commands from the ECU and perform the appropriate actions, including transmitting acoustic bursts and receiving acoustic signals.

[0023] In various implementations, chirp modulated signals are used, for example, linear frequency modulated ("LFM") chirps. A chirp is a pulse that changes frequency during transmission. An up chirp is a signal pulse that increases in frequency during transmission, and a down chirp is a signal pulse that decreases in frequency during transmission. For clarity, the examples used herein consider a linear increase or decrease, but in various implementations, the increase or decrease is not linear. The echo of the chirp may be compressed in the correlator without introducing much or any correlation noise. Thus, echo peak detection is facilitated without reducing time resolution. Furthermore, the LFM chirp tolerates Doppler frequency shifts without or with minimal increase in correlation noise. The LFM chirp can be used as a transmit pulse to measure distance to obstacles or objects located within the sensing range of the sensor system.

[0024] Other implementations use AM (amplitude modulated) signals, e.g., pulses shaped with a fixed frequency carrier. AM signaling modes may allow for the use of shorter bursts (e.g., on the order of 200-300 microseconds), shortening transmission times and increasing sensitivity to nearby obstacles. Other implementations may employ pulses with modulated carriers, e.g., pulses modulated with Biphasic Phase Shift Keying (BPSK). For clarity, the term "burst" as used herein refers to an AM (fixed frequency), BPSK (modulated), or chirp (swept frequency) pulse, which may be one of a series of bursts generated by driving a piezoelectric or other ultrasonic transducer. A chirp modulated pulse may have a longer duration than a typical AM pulse, e.g., greater than 1 millisecond, such as in the range of 2-3 milliseconds. Note that the burst length may be varied, with shorter bursts being used to facilitate detection of nearby obstacles and longer bursts being used to increase burst energy (and echo energy) for more distant obstacles. The burst length for detecting nearby obstacles may be half or a quarter of the burst length used for more distant obstacles. The sensor may be switched between modes for different detection distances.

[0025] It may be particularly useful to systematically vary the characteristic frequency (e.g., start frequency, or equivalently, center or end frequency) of a series of chirp modulated pulses, although such frequency variations may also be applied to the carrier frequency of a series of AM pulses. The frequency variations may be expressed for each pulse as a frequency displacement from a nominal characteristic frequency (e.g., a nominal start frequency or a nominal carrier frequency).

[0026] To transmit an acoustic burst, the microprocessor commands the selected transmitter to drive the output pin of the ultrasonic transducer coupled to the piezoelectric element PZ. A transformer and / or a resonant tuning network may be provided for voltage amplification and control of the resonant frequency of the transducer. The transmitter may accept a carrier frequency signal, for example, from an oscillator having a nominal frequency of 50 kHz. The transmitter may use the carrier frequency signal to generate a series of AM (amplitude modulation) or chirp pulses, each pulse corresponding to an acoustic burst. An example of a chirp pulse may be a pulse (up-chirp) with a frequency swept upward from 7 kHz below the carrier frequency to 7 kHz above the carrier frequency. Alternatively, a down-chirp may be used, where the frequency is swept linearly downward instead of upward. In some contemplated implementations, the transmitter provides a custom pattern of frequency offsets to the acoustic burst to serve as a unique signature for that ultrasonic transducer.

[0027] To receive the acoustic signal, the microprocessor commands one or both ADCs to digitize the electrical receive signal 307 from the MEMS microphone 306 and / or the receive signal 308 from the piezoelectric element 304. The digitized signal may be provided directly to the DSP for real-time processing or may be buffered in memory for later processing by the DSP or ECU. To reduce IO bandwidth requirements, the DSP may implement data compression to reduce the number of bits required to represent the ZIF IQ data or to represent the magnitude of the baseband signal. To further reduce bandwidth requirements, the DSP may perform on-chip processing for peak detection and distance estimation. Various suitable processing techniques for detecting reflections of acoustic bursts are known in the art, including commonly owned U.S. Patent Application Publication No. 2024 / 0069192, entitled "Motion-compensated distance sensing with concurrent up-chirp down-chirp waveforms," ​​which is incorporated herein by reference.

[0028] The received electrical signal is typically in the millivolt or microvolt range, so the receiver RX M , R.X. T may include an amplifier for buffering and amplifying the signal from the receive terminal. An analog or digital mixer may be included to downconvert the received signal to baseband for further filtering and processing by the DSP. The mixer, in one implementation, is an in-phase / quadrature (I / Q) digital mixer that provides zero intermediate frequency (ZIF) IQ data as its output. (Although the term "ZIF" is used herein, the downconverted signal may actually be a low intermediate frequency or "near baseband" signal.)

[0029] The DSP applies programmable methods to acquire the received signal, detect any echoes, and measure their parameters, such as time-of-flight (ToF), duration, and peak amplitude. Such methods may use threshold comparison, minimum spacing, peak detection, zero-crossing detection and counting, noise level measurement, and other customizable techniques tuned to improve reliability and accuracy. Notably, the peak detection process itself has variations, with some variations performing rising edge detection, falling edge detection, or peak maximum detection. Processing for nearby obstacle detection may be performed entirely in the controller 302, or may be shared with or delegated to an ECU or host processor, which receives certain data over a communication bus as described above.

[0030] In addition to the proximity sensing operations described above, the sensor controller 302 can monitor the received signal 307 for communications from the smart device 106. Such monitoring may be continuous or interrupted during the proximity sensing operations. Alternatively, such monitoring may be performed for a predetermined period of time after a triggering event, such as, for example, detection of motion near the vehicle, actuation of a door handle, detection of a knock or slight vibration of the vehicle. The monitoring may be performed using a configuration such as that shown in FIG.

[0031] The amplified received signal from the receiver RX is digitized by an analog-to-digital converter ADC. The DSP obtains the digitized received signal from the ADC or from a buffer in the memory MEM. The DSP can implement various modules according to instructions retrieved from a firmware memory FW, or the modules can be implemented as application specific integrated circuits. (Alternatively, the modules may be implemented by a field-programmable gate array (FPGA) or other forms of programmable logic device (PLD)). The first module converts the digitized received signal into a carrier frequency signal f C The digitized received signal can be processed by digitally mixing it with a digital signal processor (Digital Mixer) and low-pass filtering the result to downconvert the digitized received signal. The module, in one implementation, is an in-phase / quadrature (I / Q) digital mixer that provides Zero Intermediate Frequency (ZIF) IQ data as its output. (Although the term "ZIF" is used herein, the downconverted signal may actually be a low intermediate frequency or "near baseband" signal.)

[0032] The second module may be a correlation filter (CORR) having an impulse response corresponding to a time-reversed preamble or sync word pattern specified by the communication protocol of the smart device. Such a filter produces a peak when the preamble or sync word pattern is received. When the correlation filter output exceeds a predetermined threshold, the DSP may enable subsequent modules for symbol detection and clock recovery. The symbol detection and clock recovery module may perform channel equalization to obtain an equalized signal. Symbol detection may be performed by comparing the equalized signal amplitude, phase, frequency, frequency derivative, etc., to various decision thresholds. Symbol clock recovery may be performed by comparing the equalized signal characteristics to target values ​​for symbol decisions. The sequence of symbol decisions may be fed to an extraction module (EXTR). The EXTR extracts commands and other message parameter values ​​from each message frame along with optional descrambling, decoding, and error correction. The DSP may implement a state machine (SM) or other mechanism for processing the received commands and parameter values. If two-way communication is desired, the state machine module may determine an appropriate response or acknowledgement message and provide it to the transmitter (TX). The transmitter drives the ultrasonic transducer (PZ) to transmit the response or acknowledgement message as an ultrasonic or near-ultrasonic signal to the smart device. As previously mentioned, communication with the smart device may occur in a frequency range much lower than the frequency range used for proximity sensing.

[0033] 5 is a flow diagram of an example short-range communication method that may be implemented by smart device 106. In block 502, the device determines whether a connection should be attempted. The trigger for the connection attempt may be, for example, receipt of an acoustic beacon signal from the vehicle, a determination by a navigation or location tracking system that the user has returned to the vicinity of the vehicle, the opening or launching of an app on the device, a physical tap or shake of the device, or a voice command from the user. The device continues in block 502 until a trigger is detected. Once detected, the device generates an acoustic signal in block 504 that includes a connection request.

[0034] The device checks for an acoustic signal containing a response message in block 506. If a valid response message is not detected within a predetermined time window, the device checks whether a connection attempt timer has elapsed in block 508. If so, the process returns to block 502 to wait for another trigger. If not, another connection request message is sent in block 504. If a valid response message is received in block 506, the device proceeds to block 510.

[0035] In block 510, the device may select a command to be sent to the vehicle in block 512. In block 512, the device sends the command as an acoustic signal. In block 514, the device checks the acoustic signal for a response message. If a valid response message is not detected within a predetermined time window, the device checks in block 516 whether a command timer has elapsed. If so, the process returns to block 502 to wait for another trigger. If not, the command message is resent in block 512. If a valid response message is received in block 514, the device proceeds to block 518 to determine whether a further command should be sent. If so, the device returns to block 510. If not, the device returns to block 502.

[0036] The sequence of commands may vary, but may include, for example, an unlock command, an engine start command, a climate control on command, a sound system on command, and a seat repositioning command. Single commands such as a side door open command, a trunk open command, a hood release command, a sound alarm command, or a lock command are also contemplated. If supported by the driver assistance system, the commands may include a self-park command or an auto-valet command.

[0037] 6 is a flow diagram of an example short-range communication method that may be implemented by the vehicle, or more specifically, by one or more of the sensor controllers and / or by the ECU. In block 602, the vehicle determines whether a connection should be attempted. A trigger for a connection attempt may be, for example, detection of nearby motion, detection of footsteps or other sounds, activation of a door handle (or hood release, trunk latch, or fuel port door), detection of a physical knock (or kick or vibration) on the vehicle, detection of a voice command, or detection of a connection request. The vehicle continues in block 602 until a trigger is detected. Once detected, the vehicle generates an acoustic signal that includes a beacon in block 604.

[0038] The vehicle checks for an acoustic signal containing a connection request message in block 606. If a valid request message is not detected within a predetermined time window, the vehicle checks whether a connection attempt timer has elapsed in block 608. If so, the process returns to block 602 to wait for another trigger. If not, another beacon message is sent in block 604. If a valid request message is received in block 606, the vehicle proceeds to block 610.

[0039] At block 610, the vehicle may send a response message to the device. The response message may include the results of a previously sent command or other information. For example, the response message may include vehicle status information such as whether the vehicle is actively charging / fueling, charge / fuel levels, interior temperature, tire pressure, odometer readings, service alerts, etc. Other potential information includes vehicle owner or registration information, parking pass information, valet assigned ticket information. Such information may be provided by default or in response to an information request command.

[0040] After sending the response message in block 610, the vehicle may check for an acoustic signal containing another command message in block 612. If a valid command message is received, the vehicle may attempt to execute the command in block 614, after which the process moves to block 610 to acknowledge the command and communicate a response message communicating a result, e.g., whether the command was executed successfully. If a valid command message is not detected within a predetermined time window, the vehicle checks in block 616 whether a command timer has elapsed. If so, the process returns to block 602 to wait for another trigger. If not, the previous response message is resent in block 610.

[0041] Potential advantages of the above-described configuration include the ability to immediately transfer or share authorized access to a vehicle without the need to distribute or duplicate a physical key. The likelihood of lost keys may be reduced, particularly through the use of regular backups of smart devices, and access from a stolen smart device may be immediately revoked and transferred to a replacement device. Use of smart devices may enable features such as voice command-based access, alerts regarding abandoned vehicle occupants, and access to Internet-assisted services including parking facilities, rental services, and the like.

[0042] The expected range of acoustic signals from a typical smart device is limited to, for example, less than 3 meters. Out-of-band operation for ultrasonic transducer responses may be similarly limited, or in some cases range limited using proximity sensing measurements or source triangulation to determine the user's location. Such a short-distance limitation is expected to prove advantageous in terms of security against eavesdropping or so-called "man-in-the-middle" attacks.

[0043] The preceding discussion has focused on communication between smart devices and vehicles. It should be noted that the vehicle's array of ultrasonic proximity sensors also enables communication with other vehicles and with infrastructure sensors, such as ultrasonic zone / occupancy sensors used to detect when a vehicle occupies a parking spot in a multi-storey car park. Similar sensors are used to detect when a vehicle is located, for example, in front of a fuel / charging station or an entrance / exit barrier. Such communication may occur at higher frequencies than the infrastructure sensors are designed to operate at, e.g., 30 kHz to 90 kHz, but otherwise the communication process may be similar to that described above.

[0044] Vehicle-to-infrastructure communications may facilitate parking or fueling services by automating the exchange of information associated with such transactions. Other services may also be enabled, such as allowing a parking garage to quickly determine the location of a given vehicle. In the case of autonomous vehicles, the infrastructure may relay a command to a selected vehicle to move to a building entrance or some other selected location. In the case of buildings or other infrastructure with existing sensor arrays, such services may be introduced at essentially no additional cost.

Claims

1. one or more ultrasonic sensors configured for proximity sensing; a controller configured to use the one or more ultrasonic sensors to detect parking obstacles and further configured to use the one or more ultrasonic sensors to receive acoustic signals from a smart device.

2. the acoustic signal includes at least one of a lock command, an unlock command, and an alarm command; the acoustic signal is in the frequency range of 18 kHz to 25 kHz inclusive; each of the one or more ultrasonic sensors includes a MEMS (microelectromechanical system) microphone; The vehicle of claim 1 , wherein the smart device is a smartphone.

3. The controller is further configured to use the one or more ultrasonic sensors to transmit a second acoustic signal to the smart device, the acoustic signal and the second acoustic signal providing a two-way communication channel between the vehicle and the smart device; 10. The vehicle of claim 1, wherein the controller is further configured to use multiple ultrasonic sensors of the one or more ultrasonic sensors to steer a transmitted acoustic signal to the smart device.

4. one or more microphones configured for at least one of noise cancellation, voice control, emergency vehicle detection, and proximity sensing; a controller configured to use the one or more microphones to receive acoustic signals from a smart device, the acoustic signals being in a frequency range of 18 kHz to 25 kHz inclusive; The vehicle, wherein the acoustic signal includes at least one of a lock command, an unlock command, and an alarm command.

5. 1. A method of operating an advanced driver assistance system (ADAS), comprising: performing ultrasonic proximity measurements using a first frequency range via an ultrasonic proximity sensor of the ADAS; communicating with a smart device via the ultrasonic proximity sensor using a second frequency range lower than the first frequency range; the second frequency range is within the band of 20 kHz to 23 kHz (inclusive); The method, wherein the communication includes receiving at least one of a lock command, an unlock command, and an alarm command.

6. one or more ultrasonic sensors configured for proximity sensing; a controller configured to use the one or more ultrasonic sensors to transmit data to a second vehicle or an ultrasonic occupancy sensor.

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